Method of making steel wires

ABSTRACT

THE METHOD OF MAKING A HIGH STRENGTH DUCTILE COLD DRAWN WIRE FROM HOT ROLLED RODS MADE FROM COMMONLY USED STEELS INCLUDING .65 TO 1.00% CARBON, .25 TO 1.20% MANGANESE, .35% MAXIMUM SILICON, .20% MAXIMUM ALUMINUM, .05% MAXIMUM SULPHUR, .012% MAXIMUM NITORGEN, AND .05% MAXIMUM PHOSPHORUS, BUT WITH THE ADDITION OF .03 TO .15% VANADIUM AND .20% MAXIMUM MOLYBDENUM. THE HOT ROLLED ROD IS DRAWN TO FINISHED SIZE USING ONLY ONE PATENTING STEP WITH THE REDUCTION IN AREA BEING AT LEAST APPROXIMATELY 60%.

United States Patent Office 3,668,020 Patented June 6, 1972 3,668,020 METHOD OF MAKING STEEL WIRES Wilbert A. Lucht, Orange, Cnn., assignor to United States Steel Corporation No Drawing. Original application Mar. 18, 1968, Ser. No. 714,074. Divided and this application Nov. 9, 1970,

Ser. No. 88,132

Int. Cl. C2141 9/52 US. Cl. 148-12 6 Claims ABSTRACT OF THE DISCLOSURE The method of making a high strength ductile cold drawn wire from hot rolled rods made from commonly used steels including .65 to 1.00% carbon, .25 to 1.20% manganese, .35 maximum silicon, .20% maximum aluminum, .05 maximum sulphur, 012% maximum nitrogen, and .05% maximum phosphorus, but with the addition of .03 to .15 vanadium and .20% maximum molybdenum. The hot rolled rod is drawn to finished size using only one patenting step with the reduction in area being at least approximately 60%.

This application, which is a division of my copending application Ser. No. 714,084, filed Mar. 18, 1968, abandoned in favor of a streamline continuation Ser. No. 83,614, filed Oct. 23, 1970, relates to a method of making cold drawn Wires. In making cold drawn wire, especially wires to be used in stranded wire products such as wire rope, it has been necessary to M.H. patent the rod before cold drawing and then patent it at least once more before reducing to final wire size. The additional patenting step increases the cost of production and it is desired to eliminate one of the patenting steps. It has also been determined that the physical characteristics of rods and wires produced from the same heat of steel will vary considerably even at difierent locations throughout an individual rod or wire.

-I have found that by adding vanadium, either alone or with molybdenum, to steels normally used for the above purposes a more uniform product can be obtained and the rod drawn to size using only one patenting step. The invention is particularly adapted for producing large size Wires, approximately .100 inch diameter and larger, which are subjected to heavy reductions of approximately 60% or greater in production.

It is therefore an object of my invention to provide a relatively inexpensive method of making a heavily cold drawn wire from a hot rolled rod with the wire having improved physical characteristics.

This and other objects will be more apparent after referring to the following specification which describes my invention in detail.

According to my invention, I add from 0.3 to .15% vanadium and up to .20% molybdenum to the steels commonly used for making cold drawn wire with the amount of vanadium decreasing as the amount of molybdenum increases. The steels contemplated include .65 to 1.0% carbon, .25 to 1.20% manganese, .35 maximum silicon, .20% maximum aluminum, .05 maximum sulphur, .012% maximum nitrogen, .05% maximum phosphorus, .20% maximum molybdenum, 0.3-.15% vanadium, and the balance iron and other elements, such as copper, nitrogen, and chromium, in residual amounts.

A specific analysis includes .75% carbon, .74% manganese, .23% silicon, .015% sulphur, .048% aluminum, .O9% molybdenum, .05 vanadium, with the balance iron and other elements such as copper, nitrogen and chromium in residual amounts. Rods of various sizes were hot rolled from this steel. The sizes rolled include diameter, diameter and m" diameter. The 1 rod was M.H. patented and then drawn in six drafts to .150". The M.H. patenting is a conventional heat treatment in which a rod or wire is heated to approximately 1600 F. and immediately quenched in molten lead at 975 F. The time in the lead may vary dependent upon the speed of travel and length of immersion in the bath, but for rods and large size wires the time is generally about one minute. This cold drawn wire had a tensile strength of 254,000 p.s.i. with a standard deviation or 4100 p.s.i. as compared to a standard deviation of approximately 8000 p.s.i. for similar wires without the vanadium or molybdenum additions. The torsion tests showed surprisingly uniform results with seventeen 360 twists in 8" of length.

A second specific analysis includes .70% carbon, .61% manganese, .22% silicon, .021% sulphur, .013% phosphorus, .11% vanadium, with the remainder iron and usual residuals.

Although my invention contemplates cold drawing the hot rolled rod to finish size with only one patenting step, the hot rolled rods in the following examples were M.H. patented and given a relatively small reduction by cold drawing so as to obtain a uniform circular cross section for test purposes. This was done in order to accurately determine the cross sectional area so that the properties of the rod and wire could be accurately determined. Process wire so formed was then M.H. patented and given a heavy reduction to final size.

TABLE I Mechanical properties and chemical] analysis M.H. patented process Wll'e Average 0 Mn P S Tensile, p.s.i. Percent reduction area Standard Standard Steel Average deviation Average deviation Table 1 shows the properties of various steel wires after the initial cold drawing and subsequent patenting, Samples l, 2 and 3 are of the present invention while the remaining samples are similarly processed, but omit the vanadium and molybdenum. The tests indicate no substantial difference in the tensile strength, but Samples 1, 2 and 3 are much more uniform with a standard deviation substantially less than that of the other samples. The percent reduction in area indicates the better ductility properties of the steels of the present invention. While the standarddeviation for reduction in area of Samples 4 and 5 is less than that of Samples 1, 2 and 3, the percent reduction of area is so much lower that the wire is substantially poorer in quality.

Table II shows the mechanical properties of some of the wires of Table 1 when drawn to the sizes indicated with no intermediate patenting. It will be noted that the standard deviation in tensile strength is much lower for Samples 1, 2 and 3 than that of conventional wires 4, 5, 6 and 8. This indicates a uniform product. Average torsion tests were made only for wires of applicants invention and for Sample 8. This shows little difference. The average reduction in area and average elongation is shown only for the wires of applicants invention since the other steels were tested sometime previous when it was not common to perform such tests. It will be noted that the average reduction in area, while decreased as compared to the wires prior to the final reduction, is still greater than that of the wires without vanadium and molybdenum prior to the final drawing steps.

The .195 M.H. patented process Wire (Sample 2) of applicants invention was drawn a still greater amount to .063 round. Because of this greater reduction, the tensile strength is higher, but the standard deviation is still much less than that of Samples 4, 5, 6 and 8. This indicates the greater uniformity of product of this invention even when the wire is drawn to high strength levels.

While several embodiments of my invention have been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims. 7

I claim:

1. A method of making a cold drawn wire which comprises providing a hot rolled steel rod made from steel consisting essentially of .65 to 1.00% carbon, .25 to 1.20%

manganese, .35 maximum silicon, .20% maximum molybdenum, .03 to .15 vanadium, the amount of vanadium decreasing as the amount of molybdenum increases, .20% maximum aluminum, .05% maximum sulphur, .012% maximum nitrogen, .05% maximum phosphorus, and then cold drawing said rod to finished size using only one patenting step with the reduction in cross sectional area being at least approximately 2. The method of claim 1 in which the patenting step is after the hot rolled steel rod has been cold drawn to an intermediate size.

3. The method of claim 1 in which the patenting step is prior to any cold drawing.

4. The method of claim 1 in which the steel consists essentially of .70% carbon, .6l% manganese, .22% silicon, .ll% vanadium, .02% sulphur, 0.13% phosphorus, and the balance iron and other elements in residual amounts.

5. The method of claim 4 in which the patenting step is after the hot rolled steel rod has been cold drawn to an intermediate size.

6. The method of claim 4 in which the patenting step is prior to any cold drawing.

Pomp, Anton: The Manufacture and Properties of Steel Wire 1954; published by The Wire Industry Ltd., pp. 226, 227, and 231-233.

L, DEWAYNE RUTLEDGE, Primary Examiner W. W. STALLARD, Assistant Examiner US. Cl. X.R. 14812.1 

